v4.19.13 snapshot.
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
new file mode 100644
index 0000000..7d518ee
--- /dev/null
+++ b/arch/openrisc/kernel/smp.c
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
+ * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
+ *
+ * Based on arm64 and arc implementations
+ * Copyright (C) 2013 ARM Ltd.
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/irq.h>
+#include <asm/cpuinfo.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+#include <asm/time.h>
+
+static void (*smp_cross_call)(const struct cpumask *, unsigned int);
+
+unsigned long secondary_release = -1;
+struct thread_info *secondary_thread_info;
+
+enum ipi_msg_type {
+ IPI_WAKEUP,
+ IPI_RESCHEDULE,
+ IPI_CALL_FUNC,
+ IPI_CALL_FUNC_SINGLE,
+};
+
+static DEFINE_SPINLOCK(boot_lock);
+
+static void boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ /*
+ * set synchronisation state between this boot processor
+ * and the secondary one
+ */
+ spin_lock(&boot_lock);
+
+ secondary_release = cpu;
+ smp_cross_call(cpumask_of(cpu), IPI_WAKEUP);
+
+ /*
+ * now the secondary core is starting up let it run its
+ * calibrations, then wait for it to finish
+ */
+ spin_unlock(&boot_lock);
+}
+
+void __init smp_prepare_boot_cpu(void)
+{
+}
+
+void __init smp_init_cpus(void)
+{
+ int i;
+
+ for (i = 0; i < NR_CPUS; i++)
+ set_cpu_possible(i, true);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+ int i;
+
+ /*
+ * Initialise the present map, which describes the set of CPUs
+ * actually populated at the present time.
+ */
+ for (i = 0; i < max_cpus; i++)
+ set_cpu_present(i, true);
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+static DECLARE_COMPLETION(cpu_running);
+
+int __cpu_up(unsigned int cpu, struct task_struct *idle)
+{
+ if (smp_cross_call == NULL) {
+ pr_warn("CPU%u: failed to start, IPI controller missing",
+ cpu);
+ return -EIO;
+ }
+
+ secondary_thread_info = task_thread_info(idle);
+ current_pgd[cpu] = init_mm.pgd;
+
+ boot_secondary(cpu, idle);
+ if (!wait_for_completion_timeout(&cpu_running,
+ msecs_to_jiffies(1000))) {
+ pr_crit("CPU%u: failed to start\n", cpu);
+ return -EIO;
+ }
+ synchronise_count_master(cpu);
+
+ return 0;
+}
+
+asmlinkage __init void secondary_start_kernel(void)
+{
+ struct mm_struct *mm = &init_mm;
+ unsigned int cpu = smp_processor_id();
+ /*
+ * All kernel threads share the same mm context; grab a
+ * reference and switch to it.
+ */
+ atomic_inc(&mm->mm_count);
+ current->active_mm = mm;
+ cpumask_set_cpu(cpu, mm_cpumask(mm));
+
+ pr_info("CPU%u: Booted secondary processor\n", cpu);
+
+ setup_cpuinfo();
+ openrisc_clockevent_init();
+
+ notify_cpu_starting(cpu);
+
+ /*
+ * OK, now it's safe to let the boot CPU continue
+ */
+ complete(&cpu_running);
+
+ synchronise_count_slave(cpu);
+ set_cpu_online(cpu, true);
+
+ local_irq_enable();
+
+ preempt_disable();
+ /*
+ * OK, it's off to the idle thread for us
+ */
+ cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+}
+
+void handle_IPI(unsigned int ipi_msg)
+{
+ unsigned int cpu = smp_processor_id();
+
+ switch (ipi_msg) {
+ case IPI_WAKEUP:
+ break;
+
+ case IPI_RESCHEDULE:
+ scheduler_ipi();
+ break;
+
+ case IPI_CALL_FUNC:
+ generic_smp_call_function_interrupt();
+ break;
+
+ case IPI_CALL_FUNC_SINGLE:
+ generic_smp_call_function_single_interrupt();
+ break;
+
+ default:
+ WARN(1, "CPU%u: Unknown IPI message 0x%x\n", cpu, ipi_msg);
+ break;
+ }
+}
+
+void smp_send_reschedule(int cpu)
+{
+ smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
+}
+
+static void stop_this_cpu(void *dummy)
+{
+ /* Remove this CPU */
+ set_cpu_online(smp_processor_id(), false);
+
+ local_irq_disable();
+ /* CPU Doze */
+ if (mfspr(SPR_UPR) & SPR_UPR_PMP)
+ mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
+ /* If that didn't work, infinite loop */
+ while (1)
+ ;
+}
+
+void smp_send_stop(void)
+{
+ smp_call_function(stop_this_cpu, NULL, 0);
+}
+
+/* not supported, yet */
+int setup_profiling_timer(unsigned int multiplier)
+{
+ return -EINVAL;
+}
+
+void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
+{
+ smp_cross_call = fn;
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+ smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+ smp_cross_call(mask, IPI_CALL_FUNC);
+}
+
+/* TLB flush operations - Performed on each CPU*/
+static inline void ipi_flush_tlb_all(void *ignored)
+{
+ local_flush_tlb_all();
+}
+
+void flush_tlb_all(void)
+{
+ on_each_cpu(ipi_flush_tlb_all, NULL, 1);
+}
+
+/*
+ * FIXME: implement proper functionality instead of flush_tlb_all.
+ * *But*, as things currently stands, the local_tlb_flush_* functions will
+ * all boil down to local_tlb_flush_all anyway.
+ */
+void flush_tlb_mm(struct mm_struct *mm)
+{
+ on_each_cpu(ipi_flush_tlb_all, NULL, 1);
+}
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
+{
+ on_each_cpu(ipi_flush_tlb_all, NULL, 1);
+}
+
+void flush_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ on_each_cpu(ipi_flush_tlb_all, NULL, 1);
+}
+
+/* Instruction cache invalidate - performed on each cpu */
+static void ipi_icache_page_inv(void *arg)
+{
+ struct page *page = arg;
+
+ local_icache_page_inv(page);
+}
+
+void smp_icache_page_inv(struct page *page)
+{
+ on_each_cpu(ipi_icache_page_inv, page, 1);
+}
+EXPORT_SYMBOL(smp_icache_page_inv);